(10) Special rule for State, Indian tribal, and local government plans (A) Limitation to equal accrued benefit In the case of a plan maintained for its employees by any State or political subdivision thereof, or by any agency or instrumentality of the foregoing, or a governmental plan described in the last sentence of section 414(d) (relating to plans of Indian tribal governments), the limitation with respect to a qualified participant under this subsection shall not be less than the accrued benefit of the participant under the plan (determined without regard to any amendment of the plan made after October 14, 1987 ). (B) Qualified participant For purposes of this paragraph, the term “qualified participant” means a participant who first became a participant in the plan maintained by the employer before January 1, 1990 . (C) Election (i) In general This paragraph shall not apply to any plan unless each employer maintaining the plan elects before the close of the 1st plan year beginning after December 31, 1989 , to have this subsection (other than paragraph (2)(G)). (ii) Revocation of election An election under clause (i) may be revoked not later than the last day of the third plan year beginning after the date of the enactment of this clause. The revocation shall apply to all plan years to which the election applied and to all subsequent plan years. Any amount paid by a plan in a taxable year ending after the revocation shall be includible in income in such taxable year under the rules of this chapter in effect for such taxable year, except that, for purposes of applying the limitations imposed by this section, any portion of such amount which is attributable to any taxable year during which the election was in effect shall be treated as received in such taxable year.